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I read the comments regarding the use of regarding the use of bleach (or any such biocides) for the control of moulds. Although outdoor applications on stucco are very different than the indoor applications, I am of the opinion that ALL fungicides and disinfectants are virtually worthless in the realm of indoor moulds and the indoor mould issue.

Cleaning of outside surfaces, such as those described by “Prince of Lombards” in his post, presumably regard his concern for the discolorations caused by the various organisms (which probably aren’t moulds, by the way). So using a product such as bleach, which can alter the color seems an odd approach.

Probably more effective would be a brush, and a liquid detergent – or better yet, an Hotsy with some detergent.

With regards to the use of fungicides, and biocides on indoor project, it has been my 19 years experience that one way to quickly spot an amateur in the remediation field (or indeed, a charlatan) from somebody who actually knows something about the problem is via their promotion of germicides, and disinfectants. The amateur (and especially the con-man) will spend a lot of time talking about the effectiveness of such agents and how an agent kills spores or moulds etc. In fact, in a properly conducted mould remediation no such “disinfecting” agents are needed, and many agencies (such as the US EPA) discourage their use.

This is for the simple fact that an individual who is hypersensitive to a particular fungal epitope will be sensitive to the epitope regardless of the viability of the organism (i.e. a dead mould has exactly the same protein structures as a live mould, and an hypersensitive person will respond to the dead organism as well as to the living organism). Similarly, for those who are concerned about mycotoxin production; the application of a disinfectant does nothing to neutralize a mycotoxin – so what has been achieved? (The application of bleach can oxidize some mycotoxins, but if the moisture problem hasn’t been corrected, the mould will simply return). Since these are the two issues of concern vis-à-vis the adverse health effects of moulds, and disinfectants don’t address either – why fork out good money for their use?

During a properly conducted mould remediation, only the removal of the mould from the substrate is acceptable and there is no need to spray a disinfectant since if the remediation has been properly conducted, the mould will NOT come back anyway. Watch out for those who spend a lot of time telling you about the effectiveness of germicides and the like… they are the amateurs or cons with limited knowledge of proper responses to indoor moulds.

I frequently encounter “remediators” whose primary or even sole remediation strategy is to spray some kind of disinfectant (chlorine or ozone or “EPA Approved” disinfectants). This kind of remediator fills the homeowner’s head with a lot of silly nonsense that is not related to the issue (such as EPA labeling, and FIFRA registration, etc) essentially bamboozling the homeowner into thinking that the application of a fungicide or biostat is the answer to their problems. Another class of con-man is the remediator who tells the homeowner that unless a disinfectant is applied, the mould will return.

A recent peer reviewed article (1) report on a study concerning the efficacy of disinfectants demonstrated that the disinfectants were not particularly effective. In a nut shell, the authors used a variety of disinfectants and follow-up treatments on drywall that had been colonized with a variety of moulds. The disinfectants included amines, stabilized high-oxygen solutions, chlorine dioxide solutions, etc. In every case, without exception, mould growth returned to drywall sections that had been treated with each of the disinfectants.

Having said all that, disinfectants smell bad and have a tendency to partition into wood (where it stinks for a while longer) and has been implicated as the offending agent in numerous indoor air quality cases…

Regarding encapsulants: I have yet to encounter a good reason to use one and generally prohibit their use when writing specs.

(The opinions expressed here are exclusively my personal opinions and do not necessarily reflect my professional opinion, opinion of my employer, agency, peers, or professional affiliates. The above post is for information only and does not reflect professional advice and is not intended to supercede the professional advice of others.)

Then you’ll know:
1) How to get rid of it
2) How to prevent it from recurring

In different parts of the country, the material that folks colloquially refer to as “stucco” isn’t actually stucco. However, if it is stucco, then it can’t be mould (because mould can’t grow on stucco – but mould can grow on faux stucco).

However, some fungi can grow on stucco when they team up with cyanobacteria or algae(but not mould).

Of course, that leads us back to the first part of this post wherein the definition of the discoloration is:

Quote:

Originally Posted by Prince of Lombards

It's black, and it's difficult to remove.

Knowing what it is, is knowing how to get rid of it.

But then, I'm so ald fashioned, I think rain is wet.

Cheers,
Caoimhín P. Connell
Forensic Industrial Hygienist

(The opinions expressed here are exclusively my personal opinions and do not necessarily reflect my professional opinion, opinion of my employer, peers, or professional affiliates. The above post is for information only and does not reflect professional advice and is not intended to supercede the professional advice of others.)

Hellos.
I read Mr.Connell's post of 1-29-2008, with interest and read the 1999 journal article to which he refers. However, a more recent 2006 publication testing a wider range of microbes came to a different conclusion--that cleaning disinfectants were very useful, and I copy the abstract from PubMed:

The basis for some common gypsum wallboard mold remediation practices was examined. The bottom inch of several gypsum wallboard panels was immersed in bottled drinking water; some panels were coated and others were untreated. The panels were examined and tested for a period of 8 weeks. This study investigated: (a) whether mold growth, detectable visually or with tape lift samples, occurs within 1 week on wet gypsum wallboard; (b) the types, timing, and extent of mold growth on wet gypsum wallboard; (c) whether mold growth is present on gypsum wallboard surfaces 6 inches from visible mold growth; (d) whether some commonly used surface treatments affect the timing of occurrence and rate of mold growth; and (e) if moldy but dried gypsum wallboard can be cleaned with simple methods and then sealed with common surface treatments so that residual mold particles are undetectable with typical surface sampling techniques. Mold growth was not detected visually or with tape lift samples after 1 week on any of the wallboard panels, regardless of treatment, well beyond the 24-48 hours often mentioned as the incubation period. Growth was detected at 2 weeks on untreated gypsum. Penicillium, Cladosporium, and Acremonium were early colonizers of untreated panels. Aspergillus, Epicoccum, Alternaria, and Ulocladium appeared later. Stachybotrys was not found. Mold growth was not detected more than 6 inches beyond the margin of visible mold growth, suggesting that recommendations to remove gypsum wallboard more than 1 foot beyond visible mold are excessive. The surface treatments resulted in delayed mold growth and reduced the area of mold growth compared with untreated gypsum wallboard. Results showed that simple cleaning of moldy gypsum wallboard was possible to the extent that mold particles beyond "normal trapping" were not found on tape lift samples. Thus, cleaning is an option in some situations where removal is not feasible or desirable. In cases where conditions are not similar to those of this study, or where large areas may be affected, a sample area could be cleaned and tested to verify that the cleaning technique is sufficient to reduce levels to background or normal trapping. These results are generally in agreement with laboratory studies of mold growth on, and cleaning of, gypsum wallboard.

I just wanted to keep things balanced.

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